1. Field of the Invention
The present invention relates to an apparatus for distributing gobs, and more precisely it relates to an improved apparatus for actuating a scoop in a gob distributing apparatus.
2. Description of the Related Art
Generally speaking, a bottle making machine has a feeder which feeds gobs (raw materials of gobs of glass) and a gob forming machine which usually has about eight working sections to receive the gobs from the feeder.
A gob distributing apparatus to which the subject of the present invention is directed has an archwise scoop which is located below the feeder to receive the gobs and which is rotated within a predetermined angular displacement to selectively connect stationary chutes which are provided in the working sections in a concentrical arrangement to the feeder so as to distribute and feed the gobs to the working sections in a predetermined order.
In a conventional gob distributing apparatus, an actuator for rotating the scoop has a worm wheel which lies in a horizontal plane and which is provided on an outer periphery of a vertical shaft portion thereof which is rotatably supported by a body of the apparatus, and a worm which meshes with the worm wheel and which is driven by a servo-motor.
However, the worm has, as is well known, a drawback that it has a large sliding speed of a contact surface thereof, resulting in a large friction loss. Accordingly, the worm needs a powerful large drive. Furthermore, due to a frictional wear of the contact surface of the worm, a positional deviation tends to occur between the worm and worm wheel, resulting in a decreased endurance.
There is also known a gob distributing apparatus which has an annular spur gear which is provided on an outer periphery of the vertical shaft portion which is rotatably supported by the apparatus body and which lies in a horizontal plane, and a rod with a rack which engages with the spur gear. The rod reciprocally moves in a direction of the length thereof to actuate the scoop. The rod has at its one end a threaded nut in which a threaded shaft is screwed. The threaded shaft is connected to a servo-motor, so that the rod can be reciprocally moved by the servo-motor through the threaded shaft.
In this known apparatus, the drive can be made small and the possibility of a positional deviation between the spur gear and the rack can be decreased due to a small contact surface between the spur gear and the rack and only a small drive power is needed, in comparison with the first mentioned known apparatus having a worm and a worm wheel.
However, the second known apparatus needs a relatively complex mechanism for converting the rotational movement of the servo-motor to the reciprocal movement of the rod, and a ball screw or the like for ensuring a linear movement of the rack, resulting in a large and expensive apparatus.